Percussion tools



June 15, 1965 D. w. JAMER ETAL 3,189,104

PERCUSSION TOOLS Filed Sept. 9, 1960 4 Sheets-Sheet l June 15, 1965PERCUSSION TOOLS 4 Sheets-Sheet 2 \NVENTJOR lBY ATTORNY June l5, 1965 D.w. JAMER ETAL PERCUSSION TOOLS 4 Sheets-Sheet 3 Filed Sept. 9, 1960 June15, 1965 D. w. JAMER ETAL PERCUSSION TOOLS 4 Sheets-Shea?I 4 Filed Sept.9, 1960 United States Patent O 3,189,104 PERCUSSION TQOLS Douglas W.lamer, Upper Saddle River, and Richard A. Kirlrlram, Ringwood, NJ.,assignors to Atlas Copco Aktiebolag, Nacka, Sweden, a corporation ofSweden Filed Sept. 9, 196i), Ser. No. 54,864 9 Claims. (Cl. 173-154) Thepresent invention relates to percussion tools and more particularly topercussion toolsof the self-contained manually portable and operabletype powered by an internal combustion engine. Still more particularly,the invention relates to tools of the above character in which thepercussion blows transmitted to the tool bit are effected by a freehammer piston forming a part of the engine component of the tool, thereturn stroke of the piston being effected by the pressure of elasticiiuid generated by operation of the engine. In one general type of atool of this kind elastic fluid utilized to effect the return of thefree piston is provided by a portion of the combustion gases generatedby the engine and bled under pressure from the combustion chamber of theengine for the purpose. In another general type of this kind of tool anair compressor is provided, which in a preferred embodiment of engine isformed in part by a compressor portion of a power piston having a powerportion in addition to the air compressor portion.

Power tools of the kind under discussion are naturally considerablyheavier than pneumatic hand tools of equally or greater power but areadvantageously used in many situations where pneumatic tools, with theirrequirement for a supply of compressed a-ir from an outside source, artat a distinct disadvantage, since such outside source in the greatmajority of instances must be in the form of a portable engine or motordriven compressor, which is not only cumbersome and bulky but alsoinvolves a considerable capital investment. However, because of theirgreater weight as comparedwith pneumatic hand tools, many operatorsobject to the use of the self-contained engine powered tools,particularly for certain uses requiring the manually lifting of the toolby the operator, as for example in pavement breaking or the drilling oftest holes through street paving, such as asphalt, when searching forunderground leaks from gas mains and the like. In such uses the operatorwhen withdrawing the tool from a test hole or the like, must not onlylift the weight of the tool but also overcome, by

' lifting the resistance to withdrawal of the drill steel through thickpavement of asphalt or the like, which may be considerable and add up toback-breaking labor. Also, self-contained units of the kind underdiscussion may desirably be used for purposes in which power feed of thetool bit is required if exhaustive manual effort on the part of theoperator is to be avoided.

It is therefore the general object of the present invention to providean improved percussion tool apparatus of the self-contained combustionengine powered type in which fluid pressure generated as the result ofoperation of the engine is utilized to perform functions in addition toany functions relating to the ope-ration of the engine per se, suchadditional functions being effective to lighten the load of manual laborimposed on the operator. In one of its aspects this general object iseffected in accordance with the principles of the invention by theprovision 3,189,104 Patented .lune l5, 19$5 of a mobile carrier for thetool, which carrier is adapted to support the weight of the tool and tomove the tool relative to a iixed support or abutment through theactuation of fluid pressureactuated means activated by pressure iiuidgenerated as a result of the operation of the engine of theftool. Inanother of its aspects the invention contemplates the provision of afluid pressure actuated feed leg connected with the tool for effectingpower feed or retraction of the tool through actuation of the feed legby pressure fluid generated by operation of the tool engine.

In both of the phases of the invention above noted it is a furtherobject of the invention to make the fluid pressure actuated componentssuch as the carrier or the feed leg readilyA attached` to or detachablefrom the percussion tool and a still further object is to so constructsuch components that the necessary control mechanismv therefor iscarried by the detachable components, so that when they are detached bythe weight of the tool, which may be used independently of suchcomponents, will be a minimum. A still further object of the inventionis to provide a tool of -the kind described, to which differentauxiliary components such as a carrier orV a feed leg may readily beinterchangeably attached and be detached in accordance with theimmediate use to' which the tool is to he put. Other and moreV detailedobjectsof the invention and the manner in which they are attained,

' will become evident as the ensuing portion of this speciication,descriptive of, by way of example V but not limited to, suitableembodiments for carrying the invention into effect, proceeds.

In the accompanyingdrawings, forming a part of this specification: t

FIG. l is a perspective side elevation of one embodiment `of apparatusincorporating the invention;

FIG. ,2 is an elevation, partly in section and on enlarged scale, of theapparatus shown in FIG. l;V

FIG. 3 is a plan view of the portion of the apparatus shown Iin FIGS. 1and 2 below the section line 3,-3 of FIG. 2; p

FIG. 4 is a view similar to FIG. `2 and on larger scale, of a portion ofthe apparatus shown in FIGS. 1 and 2 and with the View partly inelevation and partly in section through the axis of the engine cylinder;

FIG. 5 `is a fragmentary sectional view on still larger scale of a partof the apparatus, taken on the line 5 5 lof FIG. 4;

FIG. 6 is a fragmentary longitudinal section on enlarged scale'of oneVof the supporting units of the carrie shown in FIGS. 1 and 2; i Y

. FIG. 7 is a section on enlarged scale taken on the line 7-7 of FIG. 2;i

FIG. V8 is a similar section taken on the line 8 8 of FIG. 2;

FIG.V 9 is a side elevation partly in section of another example ofapparatus embodying the invention;

FIG. 10 is a fragmentary section on enlarged scale taken on the line10-10 of FIG. 9; and

FIG. 11 is a fragmentary view similar to the lower portion of FIG. 4,illustrating another form of engine component for apparatus embodyingthe invention.

Referring now to the drawings, the apparatus illustrated in FIG. 1 andrelated figures comprises a combustion engine driven percussion toolindicated generally at 3 10. In its major respects the tool is of knownconstruction and advantageously may be of the kind disclosed in U.S.Patent No. 2,764,138, granted September 25, 1956, to G. L. B. Wahlstenet al.

As seen more particularly in FIGS. 1 and 4, the tool comprises aninternal combustion engine having a power cylinder 12 of the air-coolednned type in which there is operatively mounted a power piston 14attached by means of a connecting rod 16 to the crank shaft (not shown)of the engine, the latter being located in the crank case 18 of theengine, to which the handles 20, to be grasped by the operator of thetool, are fixed and which also carries the fuel tank 22. As seen in FIG.1 the crank case also carries a suitable starter the housing of which isindicated at 24 through the medium of which the engine may be started bythe usual rope starter the handle of which is indicated at 26.

In addition to the power piston 14 there is also mounted in the cylinder12 the free hammer piston 28 carrying at its lower end a flange 30 oflarger diameter slidably mounted in a chamber 32 formed in an axialextension 12a of the cylinder 12, and further carrying a co-axiallyextending hammer portion 28a of smaller diameter, adapted to strike atool such as a drill steel indicated at 34, the latter being carried bya casing extension 36 secured to the lower end of the cylinder 12, whichextension also carries suitable means 38 for rotating the drill, thelatter means being of known construction forming no part of the presentinvention and therefore not being described herein in detail.

The cylinder 12 is connected to crank case 18 through the medium of acasing part 40 having a bore of larger diameter than that of the bore ofcylinder 12. The power piston 14 projects into the casing 40 and at theend of the piston opposite the combustion chamber is provided with anexternal flange 14a engaging the Wall of the bore of the casing portion40, so that the chamber 42 is formed around the portion of the pistonadjacent to the ange which may be for convenience referred to as acompressor portion of the piston as distinguished from the power portionof the piston operating in the cylinder 12. The chamber 42 forms theworking chamber of an air compressor, atmospheric air being drawn intothe chamber by way of the inlet port 44 and the springloaded inlet valve46 and the compressed air being discharged from the chamber by way ofthe exhaust port 48 and the spring-loaded exhaust valve 50. Compressedair from the compressor is delivered by way of conduit 52 and transferports 54 and 56 located, respectively, above and below the flange 30 onthe hammer piston 28 to the air chamber 32, to effect the return strokeof the hammer piston, which is driven downwardly to impact the drillsteel by the power stroke of the engine. The details of the manner inwhich this action is effected by the structure herein disclosed are allwell known and fully disclosed in the aforementioned U.S. Patent No.2,764,138 to which reference may be had for detailed description of theaction of the engine, which per se forms no part of the presentinvention.

As illustrated more in detail in FIG. 5, and as also disclosed in theaforesaid Patent No. 2,764,138, air which is delivered to chamber 32 aspulsations from the compressor is converted to a pneumatic pressure ofrelatively constant value maintained at predetermined desired pressureby virtue of a metering orifice S discharging a metered quantity of airto a zone of lower pressure, which air is advantageously used as shownin FIG. 5 for blowing chips and the like from the working end of the bit34 to which the air passes by Way of the orifice 58 to the auxiliarychamber 60 and the bore 34a in the drill steel or bit.

In the particular embodiment illustrating the metering orifice 58 isshown as being formed in a removable plug, which readily permitsorifices of different ow area to be employed in adjusting the action ofthe engine.

Any suitable form of flow adjustment however may be employed as, forexample, the adjustable needle valve shown in the aforementioned patent.In the present instance, in accordance with one phase of the presentinvention, the plug 62 is advantageously provided with a second passage64 leading to the exterior of the engine and adapted to deliver airwithout material restriction from chamber 32 to a conduit 66 for usehereinafter to be described, conduit 66 advantageously being connectedwith plug 62 by means of a readily disconnectible union 63 so that flowof air through the passage 64 may readily be blocked by a suitable plugreplacing the conduit connection 66.

In accordance with one of the aforementioned aspects of the invention,there is provided, for use with a tool of the kind just brieflydescribed by Way of example, a mobile carrier indicated generally at 70,comprising a base 72 which advantageously is in 'the form of atriangularly shaped base plate at the corners of which there are mountedwheels 74 and 76, the latter being swivel or caster mounted tofacilitate the manoeuvreability of the carrier. On the base plate 72there are fixed, as by Welding, two spaced cylinder elements 78 ofsupporting units indicated generally at 8i). Cylinder elements 78receive in sliding engagement suitably packed piston elements 82, theupper ends of which are connected to a tool holder indicated generallyat 84. In the embodiment illustrated the holder 84 is in the form of aplate having horizontally extending arms 84a Welded at their ends to theupper ends of the piston rods, and an upper vertical extension 84hprovided with suitable apertures adapted to receive threaded screws orstuds to be screwed into suitable threaded sockets in the crank casestructure of the engine for attaching or detaching the tool from theholder. The holder also advantageously includes a n downwardly extendingextension or arm 84C bent at its lower end as shown at 84d to form anauxiliary or secondary support engaging the lower end of the casingextension 36 of the engine of the tool. Tool is also advantageouslyprovided with an apertured lug S3 for a purpose hereinafter to bedescribed. As seen in FIG. 2, when the tool is fixed on the carrier, lugS is not in use and projects through the opening 84e in arm 84C.

The conduit 66 connects the passage 64 and the plug 62 to the housing ofa rotary three-Way plug type valve 90, seen in FIGS. 2, 7 and 8. Thisvalve comprises a housing 92 having a cylindrical bore in which isrotatably mounted a plug .type valve member 94 adapted to be manuallyturned by means of a handle 96, the housing further being provided witha longitudinally extending internal manifold passage 98 with which theconduit 66 connects. As shown in FIG. 7 the valve member 94 is providedwith an elbow passage 109 adapted in one posiion of rotation of thevalve member to provide communication between the inlet manifold passage98 and an outlet port 102 spaced 90 from the manifold 98 andcommunicating with a conduit 104. In the same transverse section of thevalve housing as that at which the port 102 is provided, the housing isprovided with a vent port 106,I the latter port being locateddiametrically opposite the passage 98.

As seen in FIG. 8 the valve member is provided at another transversesection with a second elbow passage 108 providing communication in thesame position of the valve member as that shown in FIG. 7, between avent port 110 located in the housing diametrically opposite the inletpassage 9S, and a port 112 located 90 away from passage 98 anddiametrically opposite port 102 in the plane of FIG. 7, port 112 beingin communication with a conduit 114.

As shown more clearly from FIGS. 2, 6, 7 and 8, conduit 194 leading fromport 102 is provided with branches 10411 and 1Mb which are fixed to therespective piston elements 82 and communicate with longtudinallyextending passage 1116 located in the rod portions of the pistonelements and terminating at ports 1118 situated in chambers 121i locatedabove the pistons.

Conduit 114, leading from port 112, is similarly provided with branches114a and 114b connected to the respective piston elements andcommunicating with passages 122 in the rod portions cf the pistonelements :and terminating in transversely extending passages I124providing outlets communicating with the chambers 126 located below thepiston elements.

As will be evident from the figures, valve 90 operates to connect thepressure chambers in both cylinders in parallel with the source ofpressure liuid derived from conduit 66, and also no vent the chambers-to atmosphere.

Withthe valve in .the position shown in FIGS 7 and 8,

air under pressure is delivered by the supply conduit 66, conduit 104and its branches, and passages 116 to the chambers 12) above the pistonelements, to thereby cause the pistons to move downwardly in theirrespective cylinders and lower the holder and its attached tool relativeto the base of the carrier. This downward movement is permitted by thefact that in this position of the valve the chambers 126 below thepiston elements are vented to atmosphere by the passages 124 and 122,the conduit branches and conduit 114 and vent port 11u. If the valveplug 94 is turned 90 in counterclockwise direction from the positionshown in FIGS. 7 and 8, pressure fluid will be admitted from the supplyconduit 66 via the manifold passage 9S, conduit 114 and its branches topassages 122 and 124 to chambers 126, to raise the pistons in thecylinders, this action being permitted by venting the air from chambers120 via passages 116 and conduit 104 and its branches to port 106.

In positions of rotation of the valve plug 94 intermediate the twopositions just described, communication between the cylinder chambersand both the pressure fluid supply and the vents is cut off so that thesupporting element of the carrier may be maintained in any desired fixedposition.

As will be seen from the foregoing, the above described mechanismprovides for selective raising or lowering of the supporting componentof the carrier, and with it the tool, relative to the base of thecarrier, by simple manipulation on the part of the operator of thethree-way control valve 90.

As will be evident from FIGS. l and 2, the tool when mounted is locatedwith th-e `axis of the working cylinder and of the tool bit, which mayfor convenience be referred to as the axis of impact, located within theconfines of the triangular area defined by the location of the threecarrier wheels, thus giving the maximum of stability to the apparatus,while at the same time permitting the tool to be tilted away from avertical impact axis by pivoting the carrier about the axis of the twomajor wheels 74. In the embodiment shown the base is in the form of atriangular at plate having an opening 12S located in alignment with theaxis of the tool bit-to permit passage of the tool through the base ofthe carrier. Obviously, other specific forms and shapes of bases may beemployed for mounting the wheels and providing the required support forthe units Si).

The operation of the above described apparatus is largely obvious.Assuming for example that the apparatus is to be used for the purpose ofputting down Itest holes through an asphalt pavement, for the purpose ofdetecting the source of leakage of gas from underground mains or thelike, the mounted tool may readily be wheeled to the area to beexplored, with the tool bit lifted above the level of the Workingsurface, and, with the engine in openation and making :available -asupply of compressed lair at the conduit 66, the tool may be power fedtothe working face by appropriate manipulation of the control valve toadmit pressure fluid to the cylinder elements of the carrier above thepist-on elements therein .in order to drive the flatter downwardly tolprovide the power feed. It will be evident that the value of thedownward force which can be exerted on the -tool bit by the apparatusalong is limited to the total weight of the tool and the carrier, but ifdesired the normal weight of the carrier, since it does not have to belifted or carried by the operator, may be increased by the use ofremovable lead ballast or the like. The feeding torce applied to thecylinder may of course be augmented by downward force manually appliedby the operator of the tool. Obviously, if desired, power feed of thetool downwardly may be omitted entirely if force manually exerted by theoperator is sufficient and the labor involved not too onerous.

Assume that a test hole has been drilled by the tool bit through asphaltpavement. In such instances it has been found that as a general rulewithdrawal of the tool through the asphalt often requires the exertionof a considerable withdrawing force, and in the present instance thisrequired force is provided by the carrier, by the simple manipulation ofthe control valve to admit compressed air generated by operation oftheengine to the chambers 126 below the pistons, thus utilizing the reverseof the power feed to withdraw the tool bit from the test hole andrelieve the operator of both the manual labor of lifting the tool andthe additional labor of providing the force necessary to pull the bitfrom the bore it has created.

As further will be evident, the apparatus provided by the presentinvention does not in any way detract from the general utility of thetool itself, no appreciable weight being required to be added to thetool to enable it to be used in conjunction with the carrier, since thelatter carries all of the auxiliary equipment, such as the conduitsystem and the control valve necessary to make the apparatus effective.If the tool is to be used alone, the only change in its constructionrequired is either replacement of the plug 62 having the meteringorifice 56 with a similar plug in which the passage 64 is omitted, or byusing a simple closure plug to close the opening resulting from breakingthe union connection 68 in order to detach the tool from the carrier.

The same principles as above described may also readily be employed inorder to provide a power feed for a tool of the character described, foruse in other applications where work is to be performed against avertical or comparatively slightly inclined working face and where theuse of a carrier such as that just described would be impractical. A

In such cases the tool 10 may be advantageously provided, as shown inFIG. 9, with a power feed leg indicated generally at 130, comprising acylinder element 132 and a piston element 134. In this embodiment thecylinder element 132 is provided at one end with an axially extendingflange or projection 136 adapted to be bolted to a cooperating lug, suchas lug 88 on the housing 138 of the tool 10.

Bolt 142 provides a readily detachably hinged connection between thetool and the feed leg, and the force required to move the feed leg aboutits pivot may be adjusted byl varying fthe pressure exerted on thespring washer 146. Obviously other forms of joint may be employed.

The construction of the feed leg per se is of known form, the piston rod134:1 projecting through a suitable gland in the lower end of thecylinder 132 and having attached lthereto the usual spiked foot 14S.

In the embodiment shown the construction of the tool and its enginecomponent is the same as that previously described and in the presentinstance compressed air is delivered via a flexible conduit from thechamber 32 in the casing extension 36, to V the three-way valve 919mounted on the feed leg cylinder and having conduits 152 and 154connecting respectively with passages 156 and -158 in the feed cylinderfor supplying pressure fluid to adriano/iE tion with lthe embodiment inwhich the tool is used in conjunction with ythe wheeled carrier. Powerfeed, and if required, power retraction of the tool bit is effected bymanipulation of the valve 90 to either project the piston rod 134:1 fromcylinder 132 or retract it into the cylinder.

The provision of the lug 88 on the casing of the tool together with theprovision of suitable threaded bores for receiving the fastening studs86 for attaching the holder element of the carrier shown in FIG. 1,provides ready means for selectively and detachably combining the toolwith different components of auxiliary equipment, without involving anyincrease of size or appreciable increase in weight of the tool. Thistool may readily be used either alone as a self-contained manuallyoperable unit, or as a power fed or retracted unit supportedindependently of the operator by a mobile carrier, or provided with aseparate power feed leg.

In the embodiment shown in FIG. 9 the feed leg is illustrated as beingsupplied with pressure fluid for its operation by way of a flexibleconduit 150. However, other known means of conducting pressure fluidfrom the source of supply to the feed leg through the hinged connectionmay be employed.

While in the embodiments hereinbefore described by way of example theprinciples of the invention have been illustrated as being applied to aform of tool in which pressure fluid for actuating the hammer piston onits return stroke is compressed air generated by a separate compressorincorporated in the engine component of the apparatus, the invention isnot to be considered as limited -to apparatus in which the pressurefluid is compressed air separately generated by the engine.

In the art, it is well known to provide combustion engine poweredpercussion tools of the free hammer piston type in which the returnstroke of the hammer piston is effected by the pressure of partiallyexpanded combustion gases bled from the combustion chamber of the engineand utilized for the purpose. The present invention is equally welladapted to this known type of tool as well as to the type of tool hereindisclosed in which the pressure fluid for returning the hammer piston iscompressed air, and in FIG. 11 there is more or less diagrammaticallyillustrated in fragmentary fashion, a portion of the lower or hammerpiston end of an engine cylinder 164 in which there is located the freehammer piston 166 returned upwardly on its return stroke in well knownfashion by means (not shown) embodying passages in the casing portion16S of the tool which also carries the bit 170. As illustrated in thisfigure, combustion gases under pressure may be bled from the cylinderthrough a lpor-t 172 located to be uncovered by piston 166 before itreaches the end of its power stroke, to admit combustion gases underpressure to the feed conduit 174, in which there i-s preferably locatedan expansion chamber 176 -to reduce or damp different pressurepulsations, in order that pressure fluid at relatively constant pressuremay be delivered through conduit 17S for the purpose of actuating eithera carrier or a feed leg, such as those hereinbefore described, in lieuof the compressed air employed in the apparatus herein disclosed indetail.

From the foregoing it will be evident that the principles of theinvention may be embodied in different specific forms of apparatus andit further will be evident that certain features and advantages of theinvention hereinbefore described, may, if desired, be used to theexclusion of others.

It is therefore to be understood that the invention is intended toembrace all modifications and variations of apparatus falling within thescope of the appended claims.

What we claim is:

1. In apparatus of the character described for powering a percussiontool and for supplying pressure fluid for driving -auxiliary feedingmeans and the like to be used with said tool and having a combustionengine with a combustion cylinder` and an auxiliary cylinder coaxialtherewith, the combination which comprises a motor piston reciprocablein said combustion cylinder, a radial flange on said motor pistonreciprocable therewith in said auxiliary cylinder for compressing fluidin said auxiliary cylinder, a hammer piston reciprocable in saidcombustion cylinder -and driven by combustion in said combustioncylinder imparting impact to said percussion tool, a receiving chamberadjacent said hammer piston for receiving compressed fluid from vsaidauxiliary cylinder and for supplying said fluid to said hammer pistonfor the return thereof -after each impact stroke, a conduit in flowcommunication with said auxiliary cylinder and said receiving chamberfor carrying compressed fluid from said auxiliary cylinder to saidreceiving chamber, a connection disposed `in said receiving chamber withsaid connection having a passage disposed therein for supplying pressurefluid to said auxiliary means, and adjusting means in said connectionfor maintaining the said pressure fluid in said receiving chamber at apredetermined constant pressure.

2. Apparatus as recited in claim 1 in which said connection is a screwthreaded plug screwed into said receiving chamber Iand removabletherefrom for replacement therefor by a blocking plug when no auxiliaryfeeding and the like is to be used with said percussion tool.

3. In apparatus of the character described for powering a percussiontool and for supplying pressure fluid for driving auxiliary feedingmeans therefor and having a combustion engine with a combustion cylinderand an auxiliary cylinder coaxial therewith, and a pressurefluidoperated auxiliary feeding means -adjacent thereto, the combinationwhich comprises a motor piston reciprocable in said combustion cylinder,means driven by said motor piston and reciprocable therewith in saidauxiliary cylinder for compressing fluid in said auxiliary cylinder, ahammer piston reciprocable in said combustion cylinder and driven hycombustion in said combustion cylinder imparting impact to sai-dpercussion tool, a receiving chamber adjacent said hammer piston forreceiving compressed lluid from said auxiliary cylinder and forsupplying said fluid to said hammer piston for the return thereof aftereach impact stroke and for supplying pressure fluid to said auxiliaryfeeding means, a pipe in flow communication with said auxiliary cylinderand said receiving chamber for carrying compressed fluid from saidauxiliary cylinder to said receiving chamber, a connection disposed insaid receiving chamber with said connection having a passage disposedtherein for supplying pressure fluid to said auxiliary feeding means,adjusting means in said connection for maintaining the said pressurefluid in said receiving chamber at a predetermined constant pressure,and conduit means in flow communication with said connection and saidauxiliary means for carrying said pressure fluid from said receivingchamber to said auxiliary feeding means.

4. In apparatus of the character described for powering a percussiontool and for supplying pressure fluid for driving the feeding mechanismof a wheeled carrier upon which said tool is held and fed, and having acombustion engine with a combustion cylinder and an auxiliary cylindercoaxial therewith, and a wheeled carrier for holding the said tool in asubstantially vertical position over the surface to be worked, thecombination which comprises a motor piston reciprocable in saidcombustion cylinder, means driven by said motor piston and reciprocabletherewith in said auxiliary cylinder for compressing fluid in saidauxiliary cylinder, a hammer piston reciprooable in said combustioncylinder and driven by combustion in saidl combustion cylinder impartingimpact to said percussion tool, a receiving chamber adjacent said hammerpiston for receiving compressed fluid from said auxiliary cylinder andfor supplying said fluid to said hammer piston for 'the return thereofafter each impact stroke and for supplying pressure fluid to saidfeeding mechanism, a pipe in flow communication with said auxiliarycylinder and said receiving chamber for carrying compressed fluid fromsaid auxiliary cylinder to said receiving chamber,

a connection disposed in said receiving chamber with said connectionhaving a passage disposed therein for supplying pressure uid to saidfeeding mechanism, adjusting means in said connection for maintainingthe said pressure fluid in said receiving chamber at a prederminedconstant pressure, a tool holder disposed on said carrier' for holdingsaid tool, laterally spaced apart extensible supporting means on saidcarrier having cylinder elements fixed -to the base thereof, piston androd elements disposed in said cylinder elements with said rods connectedto said holder, conduit means in flow communication with said connectionand said extensible cylinder elements on said carrier, and control valvemeans in said conduit means for controlling the supply of pres surefluid from said connection to said cylinder elements.

5. In apparatus of the character described for powering a percussiontool which can be used manually or upon a supporting and feeding means,and for supplying pressure fluid for driving the feeding mechanism ofsaid supporting and feeding device upon which said tool can be held andhaving a combustion engine with a combustion cylinder and an auxiliarycylinder coaxial therewith, and a wheeled carrier upon which saidsupporting and feeding means is disposed, the combination whichcomprises a motor piston reciprocable in said combustion cylinder, aradial flange on said motor piston and reciprocable therewith in saidauxiliary cylinder for compressing fluid in said auxiliary cylinder, ahammer piston reciprocable in said combustion cylinder and driven bycombustion in said combustion cylinder imparting impact to said hammerpiston for driving said percussion tool, a receiving chamber adjacentsaid hammer piston for receiving compressed fluid from said auxiliarycylinder and for supplying said compressed fluid to said hammer pistonfor the return thereof after each impact stroke and for supplyingpressure fluid to said supporting and feeding means, a pipe in owcommunication with said auxiliary cylinder and said receiving chamberfor carrying compressed fluid from said auxiliary cylinder to saidreceiving chamber, a removable screw-threaded plug screwed into saidreceiving chamber and removable therefrom for replacement therefor by ablocking plug when the said auxiliary supporting and feeding means isnot in use, adjusting means in said screwthreaded plug for maintainingthe said pressure fluid in said receiving chamber at a predeterminedconstant pressure, a base disposed on said mobile carrier, a tool holderdisposed on said mobile carrier and axially spaced from said base fordetachably holding said percussion tool, expansible supporting meansdisposed on said carrier with one end thereof connected to said base andthe other end thereof connected to said tool holder for moving said toolholder toward and away from said base, conduit means in flowcommunication with said plug and said expansible supporting means forsupplying compressed fluid from said plug to said expansible supportingmeans for moving said tool holder with said percussion tool disposedthereon toward and away from said base, and valve means disposed on saidtool holder in said conduit means for controlling the supply of pressureiluid from said connection to said expansible supporting means.

6. Apparatus as recited in claim in which said base is triangular inshape with wheels disposed at each of the points of said triangularshaped base, and with the percussion tool mounted on said holder withthe axis of impact thereof located within the area of the triangledefined by said Wheels.

7. Apparatus as recited in claim 5 in which said expansible supportingmeans comprises two spaced apart piston andA cylinder units on saidmobile carrier with one end thereof disposed on said base and with theother end connected to said holder, and said holder comprises a bridgingelement connecting said units.

8i. In apparatus of the character described for powering a percussiontool and for supplying pressure iuid for driv- 10 Y ing auxiliaryfeeding means and the like to be used with said tool and having acombustion engine with a combustion cylinder and an auxiliary cylindercoaxial therewith, and a pressure iiuid actuated extensible feed legpivotally connected to said tool with cylinder and piston elements, oneof which is connected to said tool and the other of which isprovidedwith a foot adapted to engage a fixed abutment spaced from theworking face to be engaged by said tool, the combination which comprisesa motor piston reciprocable in said combustion cylinder, a radial iiangeon said motor piston and reciprocable therewith in said auxiliarycylinder for compressing fluid in said auxiliary cylinder, a hammerpiston reciprocable in said combustion cylinder and driven by combustionin said combustion cylinder imparting impact to said hammer piston fordriving said percussion tool, a receiving charnber adjacent said hammerpiston for receiving compressed uid from said auxiliary cylinder and forsupplying said fluid to said hammer piston for the return thereof aftereach impact stroke and for supplying pressure fluid to said feed leg, apipe in ow communication with said auxiliary cylinder and said receivingchamber for carrying compressed fluid from said auxiliary cylinder tosaid receiving chamber, a connection disposed in said receiving chamberwith said connection having a passage disposed therein for supplyingpressure fluid to said feed leg, adjusting means in said connection formaintaining the said pressure liuid in said receiving chamber at apredetermined constant' pressure, conduit means in flow communicationwith said connection and said cylinder and piston elements in said feedleg for conveying pressure fluid from said receiving chamber to saidfeed leg, and valvemeans in said conduit for admitting pressure liuid tosaid cylinder in said feed leg for the extension thereof and for feedingsaid tool thereon toward a surface to be worked.

9. In apparatus of the character described for powering a percussiontool and for supplying pressure fluid for driving auxiliary feedingmeans and the like to be used with said tool and having a combustionengine with a combustion cylinder and an auxiliary cylinder coaxialtherewith, and a iiuid pressure actuated extensible feed leg with acylinder element pivotally connected to said tool and a piston elementhaving a piston rod adapted to engage a surface spaced from the workingsurface of said tool, the combination which comprises a motor piston4reciprocable in said combustion cylinder, a radial flange on said motorpiston and reciprocable therewith in said auxiliary cylinder forcompressing fluid in said auxiliary cylinder, a hammer pistonreciprocable in said combustion cylinder and driven by combustion insaid combustion cylinder imparting impact to said hammer piston fordriving said percussion tool, a receiving chamber adjacent said hammerpiston for receiving compressed fluid from said auxiliary cylinder andfor supplying said uid to said hammer piston for the return thereofafter each impact stroke and for supplying said fluid to said cylinderelement in said feed leg, a pipe in flow communication with saidauxiliary cylinder and said receiving chamber for carrying compressedfluid from said auxiliary cylinder to said receiving chamber, aconnection disposed in said receiving chamber with said connectionhaving a passage disposed therein for supplying pressure uid to saidcylinder element in said feed leg, adjusting means in said connectionfor maintaining the said pressure iiuid in said receiving chamber at apredetermined constant pressure, a conduit in flow communication withsaid connection and said cylinder element for conveying said pressurefluid from said receiving chamber to saidcylinder element, and valvemeans disposed on said cylinder element in said conduit means foradmitting pressure to said cylinder element to extend said feed leg in adirection imparting feeding movement to said tool.

(References on following page) Dobbs 173-154 10 Zeiser 175-201 Wahlstenet a1. 123-7 Read 173-159 Seawright 173-153 Larcen 175-129 BROUGHTON G.DURHAM, Primary Examiner.

CHARLES E. OCONNELL, BENJAMIN HERSH,

Examiners.

1. IN APPARATUS OF THE CHARACTER DESCRIBED FOR POWERING A PERCUSSIONTOOL AND FOR SUPPLYING PRESSURE FLUID FOR DRIVING AUXILIARY FEEDINGMEANS AND THE LIKE TO BE USED WITH SAID TOOL AND HAVING A COMBUSTIONENGINE WITH A COMBUSTION CYLINDER AND AN AUXILIARY CYLINDER COAXIALTHEREWITH, THE COMBINATION WHICH COMPRISES A MOTOR PISTON RECIPROCABLEIN SAID COMBUSTION CYLINDER, A RADIAL FLANGE ON SAID MOTOR PISTONRECIPROCABLE THEREWITH IN SAID AUXILIARY CYLINDER FOR COMPRESSING FLUIDIN SAID AUXILIARY CYLINDER, A HAMMER PISTON RECIPROCABLE IN SAIDCOMBUSTION CYLINDER AND DRIVEN BY COMBUSTION IN SAID COMBUSTION CYLINDERIMPARTING IMPACT TO SAID PERCUSSION TOOL, A RECEIVING CHAMBER ADJACENTSAID HAMMER PISTON FOR RECEIVING COMPRESSED FLUID FROM SAID AUXILIARYCYLINDER AND FOR SUPPLYING SAID FLUID TO SAID HAMMER PISTON FOR THERETURN THEREOF AFTER EACH IMPACT STROKE, A CONDUIT IN FLOW COMMUNICATIONWITH SAID AUXILIARY CYLINDER AND SAID RECEIVING CHAMBER FOR CARRYINGCOMPRESSED FLUID FROM SAID AUXILIARY CYLINDER TO SAID RECEIVING CHAMBER,A CONNECTION DISPOSED IN SAID RECEIVING CHAMBER WITH SAID CONNECTIONHAVING A PASSAGE DISPOSED THEREIN FOR SUPPLYING PRESSURE FLUID TO SAIDAUXILIARY MEANS, AND ADJUSTING MEANS IN SAID CONNECTION FOR MAINTAININGTHE SAID PRESSURE FLUID IN SAID RECEIVING CHAMBER AT A PREDETERMINEDCONSTANT PRESSURE.